i. Methods and Devices for Measuring the Density of Solids Suspended in Liquid Media
Many industrial and laboratory processes require the periodic or continual measurement of the density of solid matter suspended within a liquid matrix. Such measurements are particularly commonplace in the biotechnology, water treatment, petroleum, chemical, pharmaceutical and food processing industries.
One type of instrument which has heretofore been utilized to measure the density of solid particles suspended in a liquid medium is the optical densitometer or spectrophotometer.
A spectrophotometer instrument typically comprises a light source positioned in a first location and a sensor positioned at a second location, such that light from the light source must pass through the liquid medium wherein the solid particles are suspended prior to reaching the sensor. The density of the solid particles within the liquid medium is then determined based on the relative amount of light energy transmitted from the light source to the sensor.
The existence of gas bubbles, voids or solid clusters within the liquid medium may interfere with the measurement of solids concentration by standard spectrophotometer techniques, as such gas bubbles or voids may prevent or disrupt transmission of light energy through the liquid medium.
The existence of such gas bubbles, voids or solid clusters is commonplace in systems wherein the liquid medium is under constant agitation, circulation or aeration. Accordingly, there exists a need in the art for improved methods and devices for measuring the density of suspended solids within liquid media wherein there exists numerous gas bubbles, voids or clusters such as those created by circulation, agitation or aeration of the liquid medium.